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Many small organisms self-propel in viscous fluids using travelling wave-like deformations of their bodies or appendages. Examples include small nematodes moving through soil using whole-body undulations or spermatozoa swimming through mucus using flagellar waves. When self-propulsion occurs in a non-Newtonian fluid, one fundamental question is whether locomotion will occur faster or slower than in a Newtonian environment. Here we consider the general problem of swimming using small-amplitude periodic waves in a viscoelastic fluid described by the classical Oldroyd-B constitutive relationship. Using Taylor's swimming sheet model, we show that if all travelling waves move in the same direction, the locomotion speed of the organism is systematically decreased. However, if we allow waves to travel in two opposite directions, we show that this can lead to enhancement of the swimming speed, which is physically interpreted as due to asymmetric viscoelastic damping of waves with different frequencies. A change of the swimming direction is also possible. By analysing in detail the cases of swimming using two or three travelling waves, we demonstrate that swimming can be enhanced in a viscoelastic fluid for all Deborah numbers below a critical value or, for three waves or more, only for a finite, non-zero range of Deborah numbers, in which case a finite amount of elasticity in the fluid is required to increase the swimming speed. ; This work was funded in part by the European Union through a Marie Curie CIG Grant to E.L. ; This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jtbi.2015.06.045

We discuss a procedure for seasonality analyses of short time-series data with small amplitude. Such analyses are often performed in medical research. In economics, however, time series are typically long and of appreciable amplitude; therefore, economists are used to analyzing such data. Our procedure provides one more tool for the economists' data-analysis toolbox. We illustrate the procedure's application with three examples of real economics data. The examples demonstrate that the procedure can be profitably applied to short economics time series. JEL Classifications: C12, C22, C23, C49, F31

Using the method of different scales, formulas for the hydrodynamic fields of acoustic-gravity waves (AGWs) with vertical wavelengths small compared to the scales of changes in the background temperature and wind fields are derived. These formulas are equivalent to the conventional WKB approximation, but explicitly include the vertical gradients of the background fields. The conditions for the applicability of the obtained formulas for describing the propagation of AGWs from the troposphere to the thermosphere are formulated and analyzed. The absence of singular points (critical levels) in the equations for wave modes in the analyzed height range is one of the conditions for the applicability of approximate formulas. For the wind from the empirical HWM model, singular points are often located below 200 km and are typical for internal gravity waves (IGWs), with lengths of the order of 10 km. As the wavelength increases, the number of singular points decreases. For IGWs with scales on the order of 300 km or more, there are usually no singular points. It is shown that IGWs with periods of less than 20 min propagating upward from tropospheric heights usually have one turning point in the altitude range from 100 to 130 km. The obtained formulas are useful, in particular, for parametrization of AGW effects in numerical models of atmospheric dynamics and energy.

In a context of global biodiversity threat, overexploitation of wildlife populations through hunting is of major concern. Subsistence hunting, as a source of protein and incomes, is however a major component of livelihood for some local communities. The Congo basin in Central Africa is emblematic of these challenges, with rapidly declining wildlife populations in this biodiversity hotspot and the presence of rural populations relying on the exploitation of natural resources. The elaboration of sustainable hunting and management strategies is crucial but hampered by the lack of information on the impact of hunting on the status of wildlife populations. Measuring concurrently spatial patterns of wildlife occurrence and hunting activities at different sites along a gradient of hunting pressure may provide an important basis to identify indicators of non-sustainability of hunting. In this study, we implemented a standard protocol aiming at assessing the relationship between hunting practices and wildlife occurrence over 6 hunting grounds in the Congo Basin (Gabon, Congo, and Democratic Republic of Congo). Camera traps were deployed for a month over >300 sampling stations to detect the presence of elusive forest dwelling species. Socio-economic surveys were concurrently conducted in villages to map the contours and the principal features of every hunting ground, and characterize the management rules, hunting practices, offtakes and bushmeat consumption. The data collected by the camera traps were analysed using statistical models that estimate probabilities of occurrence of focal wildlife species at each station. Our analysis identified the environmental and hunting related drivers of small- and large-scale spatial variations in occurrence for species belonging to these different indicator categories. Different categories of species were distinguished according to their potential as indicators of hunting pressure or practices. We discuss their respective relevance as a basis for implementing evidence-based wildlife management strategies through adaptive management. (Texte intégral)

The Hunting Apes: Meat Eating and the Origins of Human Behavior. Craig B. Stanford. Princeton, NJ: Princeton University Press. 1999. 254 pp.

How the Swiss government regulates the hunting of wild animals in different areas, in the largest of which hunting permits are issued, a somewhat smaller area in which permission to hunt is based on leases, and the smallest in which hunting is forbidden. Summaries in English and German.

In Andalusia, southern Spain, each game estate applies its own rules and presents its results in annual hunting reports, which have been mandatory for Spanish game estates since 1989. We used the information about hunting yields, included in 32 134 annual hunting reports produced during the period 1993/94 to 2001/02 by 6049 game estates, to determine the current distribution of hunting yields of big and small game species in Andalusia. Using generalised linear models and a geographic information system, we determined the most favourable municipalities to big and small game, respectively, and delimited potential areas to attain good hunting yields for big and small game at a 1-km2 resolution. Municipalities and areas favourable to big game are mainly located in the Sierra Morena and the westernmost fringe of the Betic Range, while those favourable to small game occupy the upper Guadalquivir River valley. There is a clear segregation between big and small game species according to the physiography and land uses of the territory. Big game species are typical of Mediterranean woodland areas, while the most emblematic small game species prefer agricultural areas. Our results provide a territorial ordination of hunting yields in southern Spain and have several potential applications in strategic planning for hunting activities and biodiversity conservation in Andalusia that can be extrapolated to other regions.

Context Recent declines in small game hunting participation are concerning because of the resulting decline in conservation funding generated from hunting. Combatting hunting participation declines requires understanding what impacts hunters' satisfaction. Literature on hunter satisfaction has primarily focused on big game hunters, elements of which may not apply to small game hunters. Aims The objective of this study was to assess the impact of various harvest and non-harvest factors on Tennessee small game hunters' satisfaction. Methods After the 2019–2020 small game hunting season ended, a sample of 15 115 Tennessee hunters and trappers was asked to participate in a mix-mode questionnaire related to their expectations, harvest, motivations, constraints, and satisfaction. Key results In total, 3994 individuals responded to the questionnaire and 1440 reported they participated in the 2019–2020 hunting and trapping season, 634 of which hunted small game. A path analysis showed that small game hunters' seasonal satisfaction was influenced by expectations, appreciative motivations, structural and interpersonal constraints, satisfaction with the number of game animals seen and harvested, use of public land, and harvest success. Conclusion Various activity-related factors significantly impact small game hunters' seasonal satisfaction. Implications These findings shed light on the various factors that influence small game hunters' seasonal satisfaction and could help wildlife agencies develop programming to help retain current small game hunters. To improve small game hunters' seasonal satisfaction, we suggest agencies focus on addressing structural constraints, fostering realistic expectations, and providing opportunities to fulfil appreciative motivations.

Abstract
Cutaneous foot receptors are important for balance control, and their activation during quiet standing depends on the speed and the amplitude of postural oscillations. We hypothesized that the transmission of cutaneous input to the cortex is reduced during prolonged small postural sways due to receptor adaptation during continued skin compression. Central mechanisms would trigger large sways to reactivate the receptors. We compared the amplitude of positive and negative post-stimulation peaks (P50N90) somatosensory cortical potentials evoked by the electrical stimulation of the foot sole during small and large sways in 16 young adults standing still with their eyes closed. We observed greater P50N90 amplitudes during large sways compared with small sways consistent with increased cutaneous transmission during large sways. Postural oscillations computed 200 ms before large sways had smaller amplitudes than those before small sways, providing sustained compression within a small foot sole area. Cortical source analyses revealed that during this interval, the activity of the somatosensory areas decreased, whereas the activity of cortical areas engaged in motor planning (supplementary motor area, dorsolateral prefrontal cortex) increased. We concluded that large sways during quiet standing represent self-generated functional behavior aiming at releasing skin compression to reactivate mechanoreceptors. Such balance motor commands create sensory reafference that help control postural sway.

Aim of study: Monitoring and control the hunting activity is primordial to guarantee its sustainability. However, the governmental agencies responsible to manage hunting commonly are unable to adequately do this job because the thousands of small private hunting states, associated exclusively by political-administrative criteria. In this work, we provided a new management tool through the establishment of a hunting regions system.Area of study: Castilla-La Mancha region, central Spain.Material and methods: We used a two-stage procedure to establish the environmental units than, afterwards, were characterized on a set of hunting variables.Main results: We generate a hunting regionalization with 12 hunting regions and proposed regional hunting yields for each of the hunting regions.Research highlights: The use of hunting regions will permit to define the game management practices more appropriately on a large scale, but also, will facilitate the tasks of assessment, management and monitoring of game of the number hunting states included in each hunting region. ; Aim of study: Monitoring and control the hunting activity is primordial to guarantee its sustainability. However, the governmental agencies responsible to manage hunting commonly are unable to adequately do this job because the thousands of small private hunting states, associated exclusively by political-administrative criteria. In this work, we provide a new management tool through the establishment of a hunting regions system.Area of study: This study was conducted at the Castilla-La Mancha region, in central Spain.Material and methods: We used a two-stage procedure to establish the environmental units than, afterwards, were characterized on a set of hunting variables.Main results: We generate a hunting regionalization with 12 hunting regions and proposed a regional hunting yields for each of the hunting regions.Research highlights: The use of hunting regions will permit to define the game management practices more appropriately on a large scale, but also, will facilitate the tasks of assessment, management and monitoring of game of the number hunting states included in each hunting region